hi.. first thing i would do is get an Amd mobo with a 710 or 750 south bridge and unlock your dormant cores/caches.
your bios should have a setting for it. if you are running at 2.6ghz fsb that means your bios's multiplier is set to 13x 200mhz. your safest bet is to get some pc2 6400 800mhz and set your bios to 4x 200mhz. ive never actually changed that setting but i am thinking about it. just got off the phone with Kingston tech support.
Phenom x4 9150e 1600mhz fsb
2GB Kingston PC2-6400 CL5
250GB WD Caviar Blue
Ati HD 4200 (for now and its better than u may think